Something you wanted to know about electrical plugs but were afraid to ask

[recyclebinned]

Anybody have any ideas as to why the prongs of an electrical plug (US plug) usually have holes cut on its tips?

[gregz]

Another cleaning edge. A dirt storage area. Hang on a hook.

Greg

[gfretwell]

usually have holes cut on its tips?

Some old receptacles had dimples on the contacts that engaged the holes. These days the best use is to install LOTO pins.

[Roanin]

From Yahoo

If you were to take apart an electrical socket and look at the contact wipers that the prongs slide into, you would find that in some cases they have bumps on them. These bumps fit into the holes so that the outlet can grip the plug's prongs more firmly. This prevents the plug from slipping out of the socket due to the weight of the plug and cord. It also improves the contact between the plug and the outlet.

[Gordon Shumway]

usually have holes cut on its tips?

They are there for our safety. When you unplug an electrical device there is still electricity trapped in the device and the power cord. Those holes allow the electricity slowly dissipate harmlessly. Without those holes life, as we know it, would cease to exist.

[krw]

Make Google Gropies ask stupid questions.

[Malcom "Mal" Reynolds]

let the water out more easily

[Domicile Dude]

"groupies" dumbshit

[krw]

Wrong, HomoGay. I meant what I wrote.

[Ashton Crusher]

They are there to dissipate static electricity.

[Art Todesco]

usually have holes cut on its tips?

Actually, there are some tiny padlocks with a very thin shackle that would easily fit into one or both of the holes to prevent someone from plugging it into power.

[DerbyDad03]

Any padlock that small wouldn't prevent someone from plugging it in, it would merely slow them down.

[DerbyDad03]

This site offers 3 possible reasons:

I've also read that they are used by manufacturers to "lock out" the plug prior to its initial use so that they can attach a note to say something like "Make sure you do (insert task here) before plugging in this device." However, I think that that's a use of them, not a reason for them.

[gregz]

I used to work with ones that had a wire wrapped through the holes. Copper I think. The other end of the wire went into a jato bottle with 1500 lbs of thrust. This was for a RCAT launching rail. You removed the wire before plugging it into some launch trigger voltage. Oh the army days....

Greg

[DerbyDad03]

Which came first, the chicken or the holes?

In other words, were the holes put there so that the copper wire could be threaded through or was the copper wire threaded through based on the convenience of the holes being present?

Remember that the original was "why we're the holes put there" not "what are the uses of the holes".

[Art Todesco]

Yup, locks are only made "to prevent drunks and kids" from getting in. I might also add, honest people.

[gfretwell]

The LOTO hardware for a 5-15 plug us a hardened wire pin with a loop on it and a somewhat regular looking padlock. The hasp of the lock goes between the prongs of the plug, under the pin and through the loop in the pin so it can't be pulled out.

This is to alert you that you are not supposed to plug it in, not prevent the dumbest person on the planet from doing it. In an industrial setting there is legal recourse against someone who defeats LOTO and injures someone. It is usually only money but it is a shitload of money.

[Ralph Mowery]

I have spent the last 20 or more years at a place and we go over LOTO many times during the year. The lock is not that important. It is the TAG. The tag is to aleart others that some work is going on and it is against the rules to defeat the tag. Just as we have some red barrier tape to be put up around some work areas. A tag must be used to aleart people who to see if you need to get in the tapped off area. Anyone can duck under the tape, but if caught without your name on the tag, you can be fired.

For plugs, another way to make them safe is a plastic clam shell type of box that goes around the plug and is then locked and tagged.

A simple plastic ty-wrap holding the tag on is just as good as the largest lock made as far as the rules go. Everyone that goes in the plant that may do some work goes through a safety course that lasts an hour or so. We have several plants that are very similar in about a 100 mile area. When someone goes from one plant to another , they go through a safety course at that plant and get a card for that plant that is only good for a year.

We are getting away from the origional question. The holes were put in the plugs because of the way the very old sockets were made and that hepled to keep the plugs in the socket and make contact. They are no longer needed, but seem to be hanging on because they were always there.

[krw]

Good locks also get people to try next door, first.

[cjt]

I thought they were there to make it less likely for the plug to weld to the socket -- sort of a "don't make the full connection all at once" thing.